Cell Counting Kit-8 Assay

MDA-MB-468 cells were seeded into 96-well plates at 8000 cells per well and incubated overnight. After 48 h of transient transfection according to the above method, the cells were treated with different concentrations of epirubicin (Macklin, China) for 48 h, or the cells were treated with different concentrations of paclitaxel (Macklin, China) for 36 h and then were assessed for viability using a CCK-8 reagent (APExBIO, USA) as per the manufacturer’s manual. Briefly, 10 μL of the CCK-8 reagent was added to each well of the 96-well plates, which were incubated for 2 h at 37°C. The optical density (OD) value at 450 nm was measured using a SpectraMax Absorbance Reader (Molecular Devices, CMax Plus, USA).